Various types of high squish, swirl developing combustion chambers have been proposed for use in spark ignition internal combustion engines intended to operate efficiently at relatively high compression ratios while controlling knock and minimizing undesirable exhaust emissions by rapid and relatively complete combustion especially of lean mixtures. In general, designs of this type have utilized guide channels or grooves in the cylinder head and/or piston to direct into the swirl chamber the mixture flow generated by the squish area as the piston approaches its top dead center position. Dual spark plugs have also been proposed. However, the use of dual spark plugs adds complexity to an engine. Further, channels and grooves in the squish area of prior high ratio compact chamber engine combustion arrangements have been indicated as a source of hydrocarbon emissions, apparently resulting from increased squish clearance at the location of these features.
Accordingly I have desired to provide a high compression ratio, high air fuel ratio, fast mass burn rate, high squish compact combustion chamber design which is capable of obtaining the desired operating advantages of high performance, knock free operation without the use of guide channels or grooves in the combustion chamber squish area. In addition it is desired to provide these advantages through the use of a highly efficient swirl chamber arrangement preferably with the use of only a single spark plug or ignition device per cylinder.